In general, in a gas laser oscillation device, a pair of electrodes are disposed in a hermetically-sealed enclosure, and a laser gas as an amplified medium filled in the enclosure is forcefully circulated by a blower unit such as a blower. The gas laser oscillation device has a configuration in which the laser gas is excited by electric discharge generated by the pair of electrodes in the enclosure, a resonator is formed by a partial reflection mirror and a total reflection mirror, and laser is output from the partial reflection mirror to the outside.
Furthermore, the gas laser oscillation device feeds irradiated laser to a machining head through an optical system including a plurality of mirrors so as to irradiate a position of a workpiece positioned on a machining table with the laser. Thus, the gas laser oscillation device is used as a light source for processing of a gas laser processing machine that carries out predetermined processing with respect to the workpiece.
In such a gas laser oscillation device, a blower unit for circulating a laser gas has a configuration in which a rotating shaft connected to an impeller for blowing the laser gas is held by a bearing, and the bearing is supplied with lubricating grease (see, for example, Patent Literature 1).
However, with such a conventional gas laser oscillation device, although grease can be appropriately supplied when grease is insufficient, the rotating shaft may rotate before the grease is sufficiently spread to a portion of the bearing in which grease is insufficient. As a result, wear and heat generation occur between the rotating shaft and the bearing, which has been one of the causes of shortening the lifetime of the bearing.